JP2019073162A - tire - Google Patents

Abstract

To easily improve on-snow performance.SOLUTION: At least part of tire width direction inner side openings 54a, 55a of outer side notches 54, 55 are positioned in a region G between a maximum position A, at which a width direction distance L is maximum at block land parts 22, 23, and an intermediate point B between adjacent two apexes Pa, Pb. Herein, an evagination deformation volume of each block land part 22, 23 to a width direction outer side at the time of grounding becomes large in the region G, and therefore, snows in center circumferential grooves 16, 17 are pushed by evagination deformation of the block land parts 22, 23 and are pushed into the outer side notches 54, 55, whereby a snow column is formed. Although the snow column is sheared at the time of withdrawal from a grounding region, a shear resistance at this time acts on a tire 11 as a grip force, and thus, on-snow performance can be easily improved.SELECTED DRAWING: Figure 2

Description

    BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a tire in which a row of block land portions consisting of a large number of block land portions is arranged in two rows in the center of a tread.

    As a conventional tire, what is described, for example in the following patent documents 1 is known.

JP, 2010-047140, A

  This structure is provided with a plurality of circumferential grooves extending in the circumferential direction of the tire and a plurality of lateral grooves connecting two adjacent circumferential grooves in the tread portion, thereby providing a large number of block land portions. In which at least two adjacent block land portion rows sandwiching the circumferential groove, the block land portions constituting them are mutually offset in the tire circumferential direction. The extending direction of the groove portion between the block land portions adjacent to each other in the tire width direction is inclined relative to the tire width direction and the tire circumferential direction, and the distance between the block land portions adjacent to the tire circumferential direction The distance between block land portions adjacent to each other in the tire width direction is shorter, and the cross-sectional length of the block land portion in the tire width direction is less from the tire circumferential direction both ends of the block land portion to the central portion of the block land portion It is those formed by partially increasing, and to improve the traction performance on a wet road surface while maintaining the wear resistance.

    Here, in recent years, in areas where there is some snowfall a few degrees a year, even if there is snowfall, it is possible to travel comfortably with normal tires without replacing with studless tires, ie normal on snow performance A tire was requested. Therefore, the inventor of the present invention has intensively researched the behavior of the tire tread at the time of snow accumulation, and in the tire as described in the above-mentioned publication, a mechanism capable of easily improving the on-snow performance without causing deterioration of other tire performance. I found out.

  This invention is made based on the above-mentioned knowledge, and an object of the present invention is to provide a tire which can improve on-the-snow performance easily.

    Such a purpose is formed in the tread central portion, and is formed on the central narrow groove extending in the circumferential direction of the tire while exhibiting a zigzag shape, and on both outer sides in the tire width direction of the central narrow groove, and extends in the circumferential direction of the tire, Forming two central circumferential grooves wider than the central narrow groove, and connecting the central narrow groove and the central circumferential groove to form a plurality of lateral grooves extending in the tire width direction and separated in the tire circumferential direction; And each block land portion row is defined between the central narrow groove and the central circumferential groove, and each block land portion row is formed into a large number of pentagons or In the tire formed of a rectangular block land portion, the block land portion is provided on the tire width direction inner side wall exposed to the central circumferential groove of the outer land portion provided respectively on the outer side in the tire width direction than the two central circumferential grooves. A plurality of outer notches extending corresponding to each other and extending outward in the tire width direction and ending in the middle of the outer land portion are formed apart from each other in the tire circumferential direction, and further, the tire width direction inner opening of the outer notches Between the maximum position A at which the tire width direction distance of the corresponding block land portion is the largest, and the midpoint B between two adjacent apexes on the tire width direction outer side wall of the block land portion This can be achieved by means of positioned tires.

    When the tire travels on a road surface covered by snow, the snow is pushed into the central circumferential groove of the tire. At this time, in the contact area, each block land portion bulges and deforms in all directions including the tire width direction outer side (outside land portion), so the snow pushed into the central circumferential groove described above It is pushed toward the outer land by the bulging deformation. Here, the amount of bulging deformation of each block land portion outward in the tire width direction is the distance in the tire width direction of the block land portion if the influence of the apex in the tire width direction outer portion of the block land portion is ignored. Each block land portion is pentagonal or hexagonal as described above, and the side wall of the lateral groove constitutes the tire circumferential direction side wall of the block land portion, although the block width) is maximized at the maximum position A. Therefore, the tire width direction distance (block width) of the block land portion is continuously reduced from the maximum position A toward both ends in the tire circumferential direction. On the other hand, when the influence of the tire width direction distance (block width) of each block land portion is ignored, the bulging deformation amount of each block land portion to the tire width direction outer side is adjacent to the block land portion at the tire width direction outer side. While it becomes almost zero at the two apexes, it increases as it gets away from the apex in the tire circumferential direction, and becomes maximum at the midpoint B of the adjacent two apexes.

  The amount of bulging deformation of each block land portion to the outer side in the tire width direction is a combined amount of the above two types of bulging deformation, but these two types of bulging deformation are the maximum position A as described above. The combined amount between the maximum position A and the middle point B becomes larger than the combined amount on both sides in the tire circumferential direction than the maximum position A and the middle point B because the weight gradually decreases as the middle point B moves away. For this reason, in the present invention, a plurality of outer notches extending in the tire width direction outward on the tire width direction inner side wall of the outer land portion and ending in the middle of the outer land portion are formed. At least a part of the tire width direction inner opening of the tire is located between the maximum position A and the middle point B, whereby the snow pushed into the central circumferential groove is cut out by the bulging deformation of the block land portion It is firmly pushed in to increase the density of the snow, and a compacted snow pillar (snow pillar) is formed in the outer notch. And such a snow pillar is sheared when the outer notch leaves the contact area (at the time of kicking), but the shear resistance at this time acts as a large grip force on the tire, and the on-snow performance of the tire Improve easily.

  According to the second aspect of the present invention, snow can be strongly pushed into the outer notch to form a high-density snow post. Furthermore, according to the third aspect of the present invention, snow pressed to the periphery of the outer notch is collected in the outer notch by the tire width direction inner side wall of the outer land portion exhibiting a parabolic shape, whereby density Snow pillars can easily be formed. According to the fourth aspect of the present invention, snow can be reliably pushed into the entire outer notch, and the strength of the entire snow pillar can be easily increased. Furthermore, according to the fifth aspect of the present invention, the snow extruded by the block land portion can be pushed into the outer notch without waste, and a high-strength snow post can be formed with certainty.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view of the tire tread which shows Embodiment 1 of this invention. FIG. It is a top view explaining the deformation | transformation state of the block which does not have an apex on the left side. It is a top view explaining the deformation | transformation state of the rectangular block which has an apex on the left side.

Hereinafter, Embodiment 1 of the present invention will be described based on the drawings.
In FIGS. 1 and 2, 11 is a normal pneumatic tire mounted on a passenger car, a truck, a bus or the like, and this tire 11 has a tread 12 made of vulcanized rubber contacting the road surface at the radially outer end. A central narrow groove 13 extending continuously along the tire circumferential direction along the tire equator S is formed in the tread central portion including the tire equator S of the tread 12, and the central narrow groove 13 is the tire equator The amount of amplitude from S is bent in the same zigzag (triangular) shape. Further, when the central narrow groove 13 is in contact with the ground, the side walls of the central narrow groove 13 (to be described later) are deformed by falling and being deformed due to load load. The tire axially inner side walls of the narrow groove 13 are brought into contact with each other, whereby the falling deformation force of the block land portion adjacent in the tire width direction is effectively transmitted. Here, in order to cause the block land portion to perform the above-described falling deformation, the groove width of the central narrow groove 13 is preferably in the range of 1.0 to 5.0 mm, more preferably in the range of 1.5 to 3.5 mm. do it.

  In the tire width direction both outer side (both tread end D sides) of the central narrow groove 13 at a position equidistant from the tire equator S, the tire circumferential direction along the tire equator S is continuous without interruption. Central circumferential grooves 16 and 17 as main grooves extending are formed and arranged, and these two central circumferential grooves 16 and 17 are bent in a zigzag shape (triangular wave shape) at the same wavelength as the central narrow groove 13. The groove width of the central circumferential grooves 16 and 17 is wider than the groove width of the central narrow groove 13 from the viewpoint of suppressing the deterioration of the wear resistance and the performance on snow, and preferably within the range of 3.0 to 10.0 mm. More preferably, the center circumferential grooves 16 and 17 and the center narrow groove 13 are disposed so as to be shifted by about 1⁄3 pitch in the tire circumferential direction while being in the range of 4.0 to 8.0 mm. In the central land portion 18 defined between the central narrow groove 13 and the central circumferential groove 16 and extending in the circumferential direction of the tire, a plurality of lateral grooves 19 extending in the tire width direction are also connected to the central narrow groove 13 and the central portion. A plurality of lateral grooves 21 extending in the tire width direction are formed in the central land portion 20 defined between the circumferential groove 17 and extending in the circumferential direction of the tire, whereby the central narrow groove 13 and the central circumferential grooves 16 and 17 are formed. And are communicated with each other by the lateral grooves 19, 21. Here, the aforementioned tire width direction includes a direction perpendicular to the tire equator S, and includes a direction inclined at an angle of less than 45 degrees with respect to the perpendicular direction.

  The lateral grooves 19 and 21 are arranged equidistantly in the tire circumferential direction, and the inner end in the tire width direction of the lateral groove 19 is at the maximum amplitude portion which is deflected to the central circumferential groove 16 side of the central narrow groove 13. The outer end of the lateral groove 19 in the tire width direction opens to the maximum amplitude portion deflected to the central narrow groove 13 side of the central circumferential groove 16, while the inner end of the lateral groove 21 in the tire width direction is the central circumferential groove 17 of the central narrow groove 13. The outer end of the lateral groove 21 in the tire width direction is open to the maximum amplitude portion which is deflected to the central narrow groove 13 side of the central circumferential groove 17. Thus, while forming one central narrow groove 13 in the tread 12 and two central circumferential grooves 16 and 17 on both sides of the central narrow groove 13 in the tire width direction, the central narrow groove 13 and the central circumferential groove are formed. If a plurality of lateral grooves 19 and 21 connecting the central narrow groove 13 and the central circumferential grooves 16 and 17 are formed in the central land portions 18 and 20 between 16 and 17, respectively, these central narrow grooves 13, A plurality of block land portions 22 and 23 spaced apart in the tire circumferential direction are defined on the central land portions 18 and 20 by the central circumferential grooves 16 and 17 and the lateral grooves 19 and 21, respectively. Here, since the central narrow groove 13 and the central circumferential grooves 16 and 17 are bent in a zigzag shape, and the lateral grooves 19 and 21 are both inclined at the same angle and in the same direction with respect to the tire width direction, the block land The portions 22, 23 have a deformed hexagonal shape, and the side walls 19a, 21a of the lateral grooves 19, 21 constitute the tire circumferential side walls of the block land portions 22, 23.

  The block lands 22 and 23 exhibiting a large number of hexagons as described above collectively constitute two rows of block lands 24 and 25 defined between the central narrow groove 13 and the central circumferential grooves 16 and 17. Do. In this embodiment, the block land portions 22 and 23 exhibiting a large number of hexagons are defined by forming the central circumferential grooves 16 and 17 in a zigzag shape, but in the present invention, the central circumferential groove is formed of a tire equator. It may be composed of grooves extending linearly along S. In this case, the block lands will be pentagonal, and the block land row will be composed of a large number of pentagonal block lands. In the tire width direction inner side walls 22a, 23a exposed in the central narrow groove 13 of each block land portion 22, 23, the tire circumferential direction central portion thereof, here, near the vertex where the inner side walls 22a, 23a intersect at an obtuse angle In order to improve drainage while suppressing deterioration in wearability, inner notches 28 and 29 extending linearly toward the tire width direction outer side walls 22b and 23b of the block land portions 22 and 23 are respectively formed. .

  Then, the inner notches 28 and 29 are terminated in the middle of the block lands 22 and 23 without reaching the central circumferential grooves 16 and 17, thereby suppressing the reduction in rigidity of the block lands 22 and 23. ing. As a result, the tire width direction distance L (the distance from the inner side walls 22a, 23a to the outer side walls 22b, 23b measured along a straight line perpendicular to the tire equator S) of each block land portion 22, 23 is the inner notch 28 The position of 29 is relatively small. In the present invention, the shape of the inner notches 28 and 29 may not be linear, but may be curved or zigzag. In addition, the outer side walls 22b and 23b of the block lands 22 and 23 exhibiting the hexagonal shape described above are long side walls 22c and 23c having a long circumferential length, and short side walls having a circumferential length shorter than the long side walls 22c and 23c. The intersections between the long side wall portions 22c and 23c and the short side wall portions 22d and 23d are the apexes Pa of one of the six apexes of the block land portions 22 and 23. It becomes.

  Outer circumferential grooves 32 and 33 extending continuously in the tire circumferential direction are respectively formed outside the central circumferential grooves 16 and 17 in the tire width direction, and these outer circumferential grooves 32 and 33 are bent in a zigzag at the same wavelength. There is. As a result, in the tire width direction outside of the two central circumferential grooves 16 and 17, more specifically, between the central circumferential groove 16 and the outer circumferential groove 32 and between the central circumferential groove 17 and the outer circumferential groove 33 Are provided with a first outer land portion 34 and a first outer land portion 36 as outer land portions extending in the tire circumferential direction, respectively, and the plurality of first outer land portions 34, 36 extend in the tire width direction Horizontal grooves 35 and 37 are respectively formed. As a result, the central circumferential groove 16 and the outer circumferential groove 32 communicate with each other by the lateral groove 35, and the central circumferential groove 17 and the outer circumferential groove 33 communicate with each other by the lateral groove 37. The lateral grooves 35 and 37 are equidistantly spaced in the circumferential direction of the tire, here, the same pitch as the lateral grooves 19 and 21. As a result, a large number of first outer blocks 38, 39 equidistantly spaced in the tire circumferential direction from the first outer land portions 34, 36 by these central circumferential grooves 16, 17, outer circumferential grooves 32, 33, and lateral grooves 35, 37. The plurality of first outer blocks 38 and 39 are generally defined between the central circumferential groove 16 and the outer circumferential groove 32 and between the central circumferential groove 17 and the outer circumferential groove 33, respectively. The first outer block row 40, 41 is divided into two rows.

  Further, second outer land portions 44, 45 extending in the tire circumferential direction are respectively defined between the outer circumferential grooves 32, 33 and the tread ends D, D, and these second outer land portions 44, 45 are defined. A plurality of lateral grooves 46, 47 extending in the tire width direction are formed respectively, and the tire width direction inner ends of these lateral grooves 46, 47 communicate with the outer circumferential grooves 32, 33, while these tire width direction outer ends are tread ends It is open to D and D. Here, the lateral grooves 46 and 47 are equidistantly spaced in the tire circumferential direction, here the same pitch as the lateral grooves 19 and 21. As a result, the outer circumferential grooves 32 and 33 and the lateral grooves 46 and 47 result in a second outer side. A plurality of second outer blocks 48, 49 equidistantly spaced in the tire circumferential direction on the land portions 44, 45 are respectively defined. The plurality of second outer blocks 48, 49 described above generally have two rows of compartments defined between the outer circumferential groove 32 and the tread end D and between the outer circumferential groove 33 and the tread end D, respectively. 2) configure the outer block row 50, 51;

  Here, the tire width direction inner side wall exposed to the central circumferential groove 16, 17 of the first outer land portion 34, 36 as the outer land portion, more specifically, the width direction inner side wall 38a of the first outer block 38, 39, A plurality of outer notches 54 and 55 respectively corresponding to the respective block land portions 22 and 23 at 39a are formed equidistantly in the tire circumferential direction, and these outer notches 54 and 55 are in the tire width direction. It extends toward the outer side (tread end D) and ends in the middle of the first outer land portions 34, 36 (first outer blocks 38, 39) without reaching the outer circumferential grooves 32, 33. In this embodiment, the outer land portion is formed of the first outer land portions 34 and 36. However, in the present invention, the outer land portion is a rib extending continuously in the circumferential direction in which the lateral groove is omitted. The outer circumferential groove may be omitted, so that it may be a single rib extending in the tire circumferential direction between the central circumferential groove and the tread end.

  And in this embodiment, in order to improve the on-snow performance without causing deterioration of other tire performances in the tire 11 as described above, the outer side notches 54 and 55 are provided at positions as described later. That is, as described above, each block land portion 22, 23 is a hexagon or a pentagon, and further, the side walls 19a, 21a of the lateral grooves 19, 21 extending in the tire width direction are side walls in the tire circumferential direction of the block land portions 22, 23. Therefore, the width direction distance L continuously increases toward the circumferential center. Here, in this embodiment, the inner side wall 22a, 23a of each block land portion 22, 23 extends to the outer side wall 22b, 23b as described above, and ends in the middle in the circumferential direction. , 29 are formed, so the width direction distance L of the block lands 22 and 23 has a significantly small value at the portions where the inner notches 28 and 29 are formed. As a result, in each block land portion 22, 23, the maximum position A at which the widthwise distance L is maximum does not exist on the inner notches 28, 29, and the tire circumferential direction from these inner notches 28, 29 Although it exists on at least one of the one side or the other side in the tire circumferential direction (at one or two places), here, one side in the tire circumferential direction having a long length in the tire circumferential direction, that is, the long side wall 22c, The maximum width position at 23 c is the maximum position A. As a result, the widthwise distance L (block width) of the above-described block lands 22 and 23 continuously decreases from the maximum position A toward both ends of the block lands 22 and 23 in the tire circumferential direction.

  Then, when the block lands 22 and 23 intrude into the ground contact area due to the running of the tire 11, the block lands 22 and 23 receive a load and are crushed in the tire radial direction. At this time, the rubber is incompressible Because of this, the side walls of the block lands 22 and 23 swell and deform in all directions including the tire width direction outer side (the first outer lands 34 and 36). Here, since the deformation toward the outside in the tire width direction is important as described later, only the deformation toward the outside in the tire width direction will be described for the bulging deformation of the block land portions 22 and 23. First, when the influence of the apexes in the tire width direction outer portions of the block land portions 22 and 23 is ignored (assuming that the apexes do not exist), how the outer side walls 22 b and 23 b are directed toward the first outer blocks 38 and 39 Consider if it will swell and deform. In this case, as shown in the schematic view of FIG. 3, the larger the distance in the width direction, the larger the deformation amount of swelling as shown by the imaginary line. Therefore, each block land portion 22, 23 (outside side walls 22 b, 23 b The bulging amount of) in the tire width direction is maximum at the maximum position A where the width L (block width) of the block lands 22 and 23 is the largest, and goes from the maximum position A to both ends in the tire circumferential direction. The distance from the maximum position A in the circumferential direction of the tire decreases continuously as the distance L in the width direction decreases. As a result, when the tire 11 travels on the road surface covered by a small amount of snow, the snow pushed into the central circumferential grooves 16 and 17 of the tire 11 is in the tire width direction of the outer side walls 22b and 23b described above. The outward bulging deformation pushes the first outer land portions 34, 36 toward the first outer land portion 34, 36, the amount of extrusion being maximum at the maximum position A and continuously decreasing away from the maximum position A.

  On the other hand, when the influence of the width direction distance L (block width) of each block land portion 22, 23 is ignored (assuming that the width direction distance is constant), the outer side walls 22 b, 23 b move toward the first outer blocks 38, 39. Consider how to swell and deform. In this case, as shown in the schematic view of FIG. 4, as the distance from the apex of the outer side wall increases, the amount of bulging deformation increases as shown by a virtual line, and therefore the block lands 22 and 23 (outside side wall 22 b , 23b) in the tire width direction increases with distance from both of the two apexes Pa and Pb and becomes largest at the most distant intermediate point B, in other words, block land The adjacent two apexes Pa and Pb in the tire width direction outer part of the portions 22 and 23 become substantially zero while increasing as the apex Pa and the apex Pb are separated in the tire circumferential direction, the adjacent two Maximum at the midpoint B between the vertex Pa and the vertex Pb.

  Here, in this embodiment, since the maximum width position located on one side in the tire circumferential direction from the inner notches 28 and 29 is adopted as the maximum position A as described above, the vertex Pb corresponds to the long side wall portions 22c and 23c As a result, the maximum position A on the tire circumferential direction side is the same side with the tire circumferential direction side wall of the block land portions 22 and 23, that is, the tire circumferential direction one side from the inner notches 28 and 29. Will be located in In the present invention, the maximum width position located on the other side in the tire circumferential direction from the inner notches 28 and 29 can be adopted as the maximum position A, but in this case, the apex Pb is the short side wall 22d, It becomes an intersection with 23d and the tire peripheral direction other side side wall of block land parts 22 and 23. From such a thing, when the tire 11 travels on the road surface covered by a certain amount of snow, the snow pushed into the central circumferential grooves 16 and 17 of the tire 11 is the above-mentioned outside side walls 22b and 23b. It is extruded toward the first outer land portion 34, 36 by the bulging deformation outward in the tire width direction, but the amount of extrusion becomes maximum at the intermediate point B and decreases continuously as it is separated from the intermediate point B. .

  The amount of bulging deformation of each of the block lands 22 and 23 to the outer side in the tire width direction is a combined amount of the two types of bulging deformation described above, but both of these two types of bulging deformation are as described above The combined amount in the region G between the maximum position A and the middle point B is smaller than the combined amount in the region H on both sides in the tire circumferential direction than the region G, because It will be great. Because of this, in this embodiment, a plurality of outer notches 54, 55 as described above are formed in the first outer land portions 34, 36 (first outer blocks 38, 39), and the outer notches are further formed. At least a part of the tire width direction inner opening 54a, 55a of the notches 54, 55 is located in the region G between the maximum position A and the middle point B in the corresponding block land portions 22, 23.

  Thereby, the snow pushed into the central circumferential grooves 16 and 17 is surely pushed into the outer notches 54 and 55 by the bulging deformation of the block lands 22 and 23, and the snow in the outer notches 54 and 55 In the outer notches 54 and 55, a compacted snow pillar (snow pillar) is formed. Moreover, the first outer land portions 34, 36 (the first outer blocks 38, 39) are also crushed in the radial direction when in the ground contact area, but at this time, the opposing side walls of the outer notches 54, 55 swell and deform As the snow that has entered the outer notches 54 and 55 is further compacted, the strength of the snow pillars increases. And such a snow pillar is sheared when the outer notches 54 and 55 separate from the contact area (at the time of kicking), but the shear resistance at this time (the reaction force of the shear force applied to the snow pillar) is It acts as a large grip on the tire 11, and the on-snow performance of the tire 11 can be easily improved. Here, since the above-described on-snow performance can be improved as the overlapping amount between the tire width direction inner openings 54a and 55a of the outside notches 54 and 55 described above and the region G is increased, the other tire performance can be improved. It is preferable to make the amount of overlap large without causing a decrease in Here, the bulging deformation of the block lands 22 and 23 (outside side walls 22b and 23b) to the outer side in the tire width direction (within the central circumferential grooves 16 and 17) as described above is the side wall of the central narrow groove 13 (block land When the inner side walls 22a and 23a) of the portions 22 and 23 contact with each other in the ground contact area, the bulging deformation of the block land portions 22 and 23 inward in the tire width direction is limited, which is a large value. As a result, the snow pushed into the central circumferential grooves 16 and 17 described above is further extruded toward the first outer land portions 34 and 36 by the bulging deformation of the block land portions 22 and 23, and the above-described on-snow performance is significantly increased. It is improved.

  In addition, when each block land portion 22, 23 is a hexagon, as described above, one of the two apexes P, here, the apex Pa, is an intersection point of the long side wall portions 22c, 23c and the short side wall portions 22d, 23d. If the other apex P, in this case the apex Pb, is constituted by the intersection of the long side wall portions 22c and 23c and the side wall of the block land portion 22 and 23 in the tire circumferential direction, the apex Pa and the apex Pb The distance between them increases and the amount of expansion of the outer side walls 22b and 23b at the middle point B increases, and as a result, the snow can be strongly pushed into the outer notches 54 and 55, and a high density snow post is obtained. It can be formed. In this embodiment, as described above, the inner side walls 22a and 23a of the block lands 22 and 23 form the inner notches 28 and 29 in the circumferential center (here, on the vertex P). In the present invention, the inside notch may be omitted. At this time, if the block land portion is a hexagon, the maximum position A is present at one or two places on the vertex, but in the case of two places, either one may be set as the maximum position A. Then, as described above, when there are two maximum positions A and the maximum position A is located on the vertex of the inner sidewall of the block land portion, the region G and the maximum position A The outer side wall is located on the same side in the circumferential direction (one side in the circumferential direction or the other side in the circumferential direction) from the vertex of the outer side wall. In addition, when the block land portion is a pentagon, the maximum position A is only one, that is, only on the vertex of the inner side wall of the block land portion.

  And in this embodiment, the tire width direction inner side walls 38a, 39a of the first outer land portions 34, 36 (first outer blocks 38, 39) are positioned on both sides in the tire circumferential direction of the outer notches 54, 55. The two parts are crossed at a crossing angle J of more than 90 degrees and less than 180 degrees, that is, an obtuse angle. In this way, the snow pressed against the outer notches 54 and 55 due to the above-described bulging deformation can be parabola-shaped on the tires of the first outer lands 34 and 36 (first outer blocks 38 and 39). The lateral notches 54, 55 can be gathered by the widthwise inner side walls 38a, 39a, so that a high density snow post can be easily formed. Preferably, the length M of the outer notches 54 and 55 is smaller than the groove width N of the central circumferential grooves 16 and 17. The reason is that the length of the outer notches 54, 55 is a relatively small value, and the snow can be reliably pushed into the entire outer notches 54, 55 so that the overall strength of the snow post can be easily increased. .

  Furthermore, in this embodiment, the groove width center line Q of the outer notches 54, 55 is perpendicular to the outer side walls 22b, 23b of the corresponding block lands 22, 23, here long side walls 22c, 23c, or Crosses at an angle that approximates a right angle. In this way, the extruded snow due to the bulging deformation of the block lands 22 and 23 can be pushed into the outer notches 54 and 55 without waste, and a high-strength snow post can be formed with certainty. Further, in order to form a high-strength snow post, it is preferable to extend the outer notches 54 and 55 linearly with a constant width as in this embodiment. The hexagon described above is slightly changed, for example, the vertex Pa as shown by a phantom line in FIG. 2 in order to smooth the flow of water in the central circumferential grooves 16 and 17 to improve drainage performance. What partially removed near the block equator 22 and 23 near the tire equator S is also included. In this case, the vertex Pc is one of the adjacent vertices, and the midpoint between the vertex Pc and the vertex Pb is the midpoint B. Moreover, in this embodiment, although this invention was applied to a normal tire, you may apply this invention to winter tires, such as a studless tire and a snow tire.

  The present invention can be applied to the industrial field of a tire in which a block land portion row consisting of a large number of block land portions is disposed in the center of a tread.

11 ... tire 12 ... tread
13 ... central narrow groove 16, 17 ... central circumferential groove
19, 21 ... lateral groove 19a, 21a ... side wall
22, 23 ... block land portion 22a, 23a ... inner side wall
22b, 23b ... outer side wall 22c, 23c ... long side wall portion
22d, 23d ... short side wall portion 24, 25 ... block land row
34, 36 ... outside land part 54, 55 ... outside notch
54a, 55a ... inside opening Pa, Pb ... vertex

Claims (5)

    A central narrow groove is formed in the tread central portion and extends in the circumferential direction of the tire while exhibiting a zigzag shape, and is formed on both outer sides in the tire width direction of the central narrow groove and extends in the circumferential direction of the tire and wider than the central narrow groove The central narrow groove and the central narrow groove communicate with each other, and a plurality of lateral grooves extending in the tire width direction and separated in the tire circumferential direction are formed to communicate with the central narrow groove. The block land portion row is defined in two rows between the central circumferential groove and each block land portion row is formed from a large number of pentagonal or hexagonal block land portions in which the side wall of the lateral groove is the tire circumferential direction side wall In the constructed tire, the block land portion corresponds to the tire width direction inner side wall exposed in the center circumferential groove of the outer land portion provided respectively on the outer side in the tire width direction than the two center circumferential grooves, A plurality of outer notches that extend outward in the width direction and end in the middle of the outer land portion are formed apart from each other in the tire circumferential direction, and at least a part of the tire width direction inner opening of the outer notches It is characterized in that it is located between the maximum position A where the tire width direction distance of the corresponding block land portion is maximum and the middle point B of two adjacent apexes on the tire width direction outer side wall of the block land portion. To be a tire.     Each block land portion is formed into a hexagon by forming the central circumferential groove in a zigzag shape, while the outer side wall in the tire width direction of the block land portion is a long side wall portion, and a short side wall whose circumferential length is shorter than the long side wall portion And one of the two apexes is formed from the intersection of the long side wall and the short side wall, and the other is formed from the intersection of the long side wall and the tire circumferential side wall of the block land. The tire of 1.     The tire according to claim 1 or 2, wherein in the tire width direction inner side wall of the outer land portion, portions of the outer notch located on both sides in the tire circumferential direction intersect at an obtuse angle.     The tire according to any one of claims 1 to 3, wherein a length of the outer notch is smaller than a width of the central circumferential groove.     The tire according to any one of claims 1 to 4, wherein the groove width center line of the outer notch intersects at a right angle or an angle approximating a right angle with the tire width direction outer side wall of the block land portion. .

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